Engine-generators applied to combat maneuvering systems, such as main battle tanks or armored vehicles, are devices for converting chemical energy contained in fuel, such as gasoline or diesel, into electrical energy via mechanical energy.
Generally, such an engine-generator functions to supply electric power to a series hybrid electric combat maneuvering systems. The series hybrid electric combat maneuvering system is configured such that a drive source, such as a drive motor, drives a vehicle using the electric power supplied from the engine-generator.
Electrical energy produced by the engine-generator may be directly supplied to an electrically-driven motor or may be used to charge a battery and then be reused later. Generally, an engine-generator control method applied to a series hybrid electric combat maneuvering system is basically operated only at an Optimal Operating Point (OOP) at which the efficiency of the engine-generator is best, and determines whether to operate the engine-generator depending on the State Of Charge (SOC) of a battery.
That is, such an engine-generator control method is a scheme for, if the SOC of the battery is decreased to a predetermined level or less, turning on the engine-generator, and if the SOC is increased to the predetermined level or more, turning off the engine-generator, and consistently operating the engine-generator at OOP.
Even though the engine-generator control method can improve the efficiency of the engine-generator itself using the method, the amount of charge/discharge current of a battery is excessively increased, thus deteriorating the efficiency of the overall system. Such an excessive current of the battery may increase the fluctuation of the battery voltage, thus various electronic parts.
Further, such an engine-generator control method is disadvantageous in that the accelerator pedal of a vehicle and the operating point of the engine are independent, so the feel of driving is greatly different from that of conventional vehicles and is generally unpleasant to the driver, and in that a point corresponding to OOP typically denotes a high-powerpoint, so that the engine is always operated at high power and then can be damaged.
Furthermore, such an engine-generator control method is disadvantageous in that if the engine is turned off after the vehicle has stopped while the engine-generator is charging the battery due to low SOC, the engine suddenly stops.